Search Results (83)

Additive manufacturing of NiTi shape memory alloys is challenging due to their sensitivity to composition and thermal history. The gap between high-resolution powder-based AM and high-productivity wire-based processes for NiTi remains a challenge. This study investigates the technical feasibility of depositing Ni-rich NiTi (56 wt.% Ni) using a micro gas metal arc-based directed energy deposition (µ-GMA-DED) process with a 300 µm wire. The investigation was conducted on a single-bead, single-layer geometry deposited onto a titanium substrate. The deposited layer exhibited a heterogeneous microstructure with dendritic and eutectic-like regions, where phase analysis revealed a mixture of NiTi and Ni₃Ti intermetallics. Differential scanning calorimetry showed suppression of the martensitic transformation in the as-deposited condition, likely due to the high fraction of non-transformable Ni₃Ti, compositional redistribution during rapid solidification, and potential substrate dilution. The nanoindentation results reflected this heterogeneity, with Young’s modulus ranging from 64 to 151 GPa. While post-deposition heat treatment partially restored the martensitic transformation, these results demonstrate the preliminary feasibility of the µ-GMA-DED process, noting that strict control over chemistry and dilution is required before the route can be applied to functional components. Full article

This research investigated the performance of spark-plasma erosion-based machining, also known as electrical discharge machining, for micro-hole drilling in SS316L and Ti-6Al-4V under various spark-plasma formation conditions, with 27 experimental combinations of capacitance, voltage, and electrode feed rate. Spark-plasma conditions at various discharge energies were found to play a major role in influencing machining time and overcut, which were considered two responses to evaluate machining performance. Increasing the voltage from 80 to 180 V at 100 pF decreased machining time from 2553 s to 564 s for SS316L and from 2608.2 s to 570.6 s for Ti-6Al-4V, but it increased overcut from 6 to 17.5 µm and from 8 to 22 µm, respectively. At 10,000 pF and 180 V, machining times of 51.6 s (SS316L) and 62.4 s (Ti-6Al-4V) were obtained, with maximum overcut values of 62.5 µm and 73.5 µm, respectively. Analysis of variance revealed that voltage strongly controlled machining time (~64%), while capacitance dominated overcut (64–69%). Ti-6Al-4V required 5–20% more machining time and exhibited a higher overcut due to its lower thermal conductivity and higher strength. The experimental observations indicated consistent plasma formation and favorable spark to achieve the required geometric accuracy and process productivity for the fabrication of high-quality biomedical components from SS316L and Ti-6Al-4V. Full article

Meltblown polypropylene (PP) nonwoven fabrics are widely used in medical and daily protective facemasks. However, the incorporation of nanomaterials such as titanium dioxide nanoparticles (nano-TiO₂) into meltblown PP structures remains insufficiently investigated, particularly regarding the physical and thermophysiological comfort properties of facemask materials. This study investigated the weight, thickness, morphology, air permeability, water vapour permeability, and moisture management properties of meltblown PP nonwoven fabrics incorporated with different concentrations of nano-TiO₂. A commercial 3-ply meltblown PP facemask and laboratory-fabricated 3-ply facemasks containing 5% and 10% nano-TiO₂ were tested. The 3-ply with 10% nano-TiO₂ facemask showed increases in fabric weight and thickness of 58% and 64%, respectively, compared to the commercial facemask. The SEM and EDX confirmed the deposition of TiO₂ nanoparticles on the fabric surfaces. In terms of comfort performance, the 10% nano-TiO₂ facemask demonstrated the highest air permeability with approximately 197.27 + 3.95 mm·s⁻¹, while water vapour permeability values for all samples were similar, ranging between 123 and 125 g·h⁻¹·m⁻². The moisture management tests exhibited a low liquid transport in all samples due to the hydrophobicity of polypropylene. Overall, the study shows the development of facemask material with enhanced structural properties and acceptable comfort performance. Full article

To overcome the limitations imposed by the intermittent nature of sunlight in photocatalytic applications, this research constructs a round-the-clock purification system. We integrated an optimized S-scheme CoFe₂O₄/BiVO₄ (CFO/BV) heterojunction (synthesized via ultrasonic self-assembly at a 0.5:0.5 ratio) with a thermal energy storage (TES) unit consisting of SiO₂-encapsulated Na₂SO₄·10H₂O phase change materials (PCMs). Comprehensive characterization techniques, including XRD, HRTEM, UV-Vis DRS, EPR, and DSC, confirmed the successful formation of the interface, a broadened visible-light response (λ > 650 nm), efficient radical production, and a high latent heat storage capacity (>200 J/g). Under simulated solar irradiation, the composite exhibited superior performance, degrading 98% of the Rhodamine B within 6 h (k = 0.00994 min⁻¹), significantly surpassing single-component counterparts. More importantly, during the subsequent 12 h dark period, the heat released from the PCM maintained the reaction temperature above 35 °C, driving a 64% degradation efficiency via a thermocatalytic pathway. The system demonstrated robust stability (>90% efficiency after five cycles), excellent magnetic recoverability (98%), and high tolerance to saline textile wastewater (<10% activity loss). Furthermore, Life Cycle Assessment (LCA) indicated a 40% reduction in energy consumption compared to conventional UV/TiO₂ processes, highlighting a sustainable strategy for continuous wastewater remediation through synergistic photocatalysis and thermocatalysis. Full article

Flexible biosensors offer rapid and low-cost diagnostics but are often limited by the mechanical and electrochemical instability of polymer-based designs in biological media. Here, we introduce a metallic flexible microcrack transducer that exploits the intrinsic deformability of superelastic nickel–titanium (NiTi) for label-free impedimetric detection. Mechanical bending of NiTi wires spontaneously generates martensitic-phase microcracks whose metal–gap–metal geometry forms the active transduction sites, where functional interfacial layers and captured analytes modulate the local dielectric environment and govern the impedance response. Our approach imparts a novel dielectric character to the alloy, enabling its unexplored application in the megahertz (MHz) frequency domain (0.01–10 MHz) where native NiTi is merely conductive. Functionalization with Escherichia coli (E. coli)-specific antibodies renders these microdomains biologically active. This effectively transforms the mechanically induced microcracks into tunable impedance elements driven by analyte binding. The γ-bent NiTi sensors achieved stable and quantitative detection of E. coli ATCC 25922 in sterile human urine, with a detection limit of 64 colony forming units (CFU) mL⁻¹ within 45 min, without redox mediators, external labels, or amplification steps. This work pioneers the use of martensitic microcrack networks, mimicking self-healing behavior in a superelastic alloy as functional transduction elements, defining a new class of metallic flexible biosensors that integrate mechanical robustness, analytical reliability, and scalability for point-of-care biosensing. Full article

The expensive nature and limited availability of platinum (Pt) cathodes pose a significant challenge for the widespread adoption of microbial fuel cell (MFC) technology. Although many alternatives have been studied, very few reports provide a systematic head-to-head comparison of different Ni–oxide cathodes under the same operational conditions. This research investigates cost-effective nickel-based metal oxide composites (Ni–TiO₂, Ni–Cr₂O₃, Ni–Al₂O₃) as catalysts for the oxygen reduction reaction (ORR), using Pt as a reference point. The performance of the MFC was thoroughly evaluated in terms of power output, chemical oxygen demand (COD) removal, and Coulombic efficiency (CE). The Pt cathode exhibited the highest performance (275 mW m⁻², 87% COD removal, 35% CE), confirming its catalytic advantages. Among the alternative materials, the Ni–TiO₂ composite yielded the best outcomes (224 mW m⁻², 79% COD removal, 17.7% CE), markedly surpassing the performances of Ni–Cr₂O₃ (162 mW m⁻², 72%, 24% CE) and Ni–Al₂O₃ (134 mW m⁻², 64%, 11.6% CE). Koutecký–Levich analysis clarified the mechanisms at play: Pt facilitated a direct 4-electron ORR process, while the composites operated through a 2-electron mechanism. Notably, the semiconductor properties of Ni–TiO₂ resulted in a higher electron transfer number (n = 2.8) compared to the other composites (n ≈ 2.3), which accounts for its increased efficiency. With its low production cost, Ni–TiO₂ presents an exceptional cost-to-performance ratio. By linking catalytic performance directly to the electronic nature of the oxide supports, this study offers clear design guidelines for selecting non-precious cathodes. The dual evaluation of electrochemical efficiency and cost-to-performance distinguishes this study from prior reports and underscores its practical significance and originality. This study highlights Ni–TiO₂ as a highly sustainable and economically viable catalyst, making it a strong candidate to replace Pt for practical MFC applications that focus on simultaneous power generation and wastewater treatment. Full article

Background: Mental health problems are increasingly common among children and adolescents, making schools a key setting for health promotion. Nurses can play a central role in prevention and support, but in Chile, the role of the school nurse has not yet been formally established. Understanding nursing students’ experiences in school-based mental health promotion can inform curriculum development and strengthen professional identity. Methods: A qualitative study with a phenomenological approach was conducted with third-year nursing students enrolled in a mental health course (N = 64). Data was collected through six individual interviews and one focus group, transcribed verbatim and analyzed using ATLAS.ti 25.0.1^®. To ensure rigor, the study was guided by the Consolidated Criteria for Reporting Qualitative Research (COREQ), and trustworthiness was ensured following Lincoln and Guba’s criteria. Results: Five main categories emerged: nursing’s role in mental health promotion; perceptions of health promotion as prevention; use of the educational process, with difficulties in formulating objectives; perceived self-efficacy, marked by initial uncertainty in working with children; and experiences in implementing projects, including reflections on the professional role, mixed feelings, facilitators, barriers, and coping strategies. Facilitators included faculty support, teacher collaboration, and group cohesion, while barriers were related to limited experience, challenges in managing children, and external conditions such as noise and unsuitable classroom conditions. Conclusions: School-based practicums in mental health promotion are valuable opportunities to integrate theory and practice, strengthen professional identity, and develop communication. Strengthening undergraduate curricula with systematic training in these areas is essential for preparing nurses for their role in school and community health. Integrating these experiences into clinical and assistive practice can enhance early detection, interprofessional collaboration, and the promotion of healthier school environments. Full article

Titanium (Ti)-based implants are widely used for bone injuries but suffer from poor bioactivity. To address this, we propose an innovative synergistic approach that combines laser melting deposition (LMD) for the fabrication of titanium-based supports with laser direct writing via two-photon polymerization (LDW via TPP) for their functionalization with 3D polymeric microstructures. We functionalized Ti surfaces fabricated by LMD using Ti (99.85 wt.%) and TiC powders (79.95 wt.% Ti, 20.05 wt.% C), with 3D microstructures obtained by LDW via TPP. The 3D microstructures were made of IP-Dip photopolymer and comprised 64 vertical microtubes arranged in five layers (10 to 170 μm tall, >94% porosity). When seeded with MG-63 osteoblast-like cells, the Ti-based surfaces functionalized with 3D polymeric microstructures promoted 3D cells’ spatial organization. Moreover, the cells seeded on functionalized Ti-based surfaces showed earlier organic matrix synthesis (day 7 vs. day 14) and mineralization (higher deposits of calcium and phosphorus, starting from day 7), as compared with the cells from non-functionalized Ti. In addition, the traction forces exerted by the cells on the 3D microstructures, determined using FEBio Studio software, were of the order of hundreds of µN, whereas if the cells would have been seeded on extracellular matrix-like materials, the traction forces would have been of only few nN. These results point towards the major role played by 3D polymeric microarchitectures in the interaction between osteoblast-like cells and Ti-based surfaces. Overall, the functionalization of Ti-based constructs fabricated by LMD with 3D polymeric microstructures made by LDW via TPP significantly improved Ti bioactivity. Full article

Anatase is well known for its photocatalytic properties. However, it can be irreversibly transformed into rutile at temperatures above 600–850 °C. This is a major limitation for ceramic tiles with self-cleaning properties, which are usually single-fired at 1100–1250 °C. To avoid this issue, functionalized tiles are often produced by double firing, where the second firing stays below 850 °C. Supporting TiO₂ on kaolinite helps to stabilize the anatase phase even at temperatures above 850 °C. In this study, a photocatalytic coating was specially developed to be suitable for the single-firing ceramic tile process. TiO₂ and TiO₂ with Nb₂O₅ (from 0 to 12 wt.%) were supported on kaolinite. This material was mixed with a glass frit to create a surface texture typical of ceramic tiles. The coated tiles were single-fired at 1185 °C. The self-cleaning performance was evaluated using contact angle (CA) measurements and methylene blue (MB) degradation under UV-A light, on both unpolished and polished surfaces. The polished sample containing 12 wt.% TiO₂ showed the best photocatalytic activity: it degraded 57% of MB and the contact angle decreased from 64° to 30° after UV-A exposure. XPS, FTIR, and FEG-SEM analyses confirmed the effective presence of TiO₂. The results demonstrate that kaolinite-supported TiO₂ is a promising approach for producing self-cleaning ceramic tiles using a single-firing process. Full article

Topological insulators (TIs) hold considerable promise for the advancement of optoelectronic technologies, including spectroscopy, imaging, and communication, owing to their remarkable optical and electrical characteristics. This study proposes a novel combination of Bi${}_2$Se${}_3$ TIs and ReSe${}_2$ for self-powered broadband photodetectors with high sensitivity and fast response time. The Bi${}_2$Se${}_3$/ReSe${}_2$ heterojunction photodetector achieves broadband response spectra ranging for 375 nm to 1 $\mathsf{\mu }$m. It demonstrates a significant responsivity of 64 mA/W at a wavelength of 600 nm (1 mW/cm${}^2$), exhibits a rapid response speed of 345 $\mathsf{\mu }$s rise/336 $\mathsf{\mu }$s fall time, and has a 3 dB bandwidth of 1.4 kHz under zero-bias conditions. The high performance can be attributed to the suitable energy band structure of Bi${}_2$Se${}_3$/ReSe${}_2$ and high carrier mobility in surface states of Bi${}_2$Se${}_3$. Excitingly, self-powered TIs photodetectors allow for high-quality signal transmission. The TIs employed in photodetectors can stimulate the production of new optoelectronic features, but they could also be used for highly integrated photonic circuits in the future. Full article

Arc scanning synthetic aperture radar (ArcSAR) can achieve high-resolution panoramic imaging and retrieve submillimeter-level deformation information. To monitor buildings in a city scenario, ArcSAR must be lightweight; have a high resolution, a mid-range (around a hundred meters), and low power consumption; and be cost-effective. In this study, a novel high-resolution wide-beam single-chip millimeter-wave (mmwave) ArcSAR system, together with an imaging algorithm, is presented. First, to handle the non-uniform azimuth sampling caused by motor motion, a high-accuracy angular coder is used in the system design. The coder can send the radar a hardware trigger signal when rotated to a specific angle so that uniform angular sampling can be achieved under the unstable rotation of the motor. Second, the ArcSAR’s maximum azimuth sampling angle that can avoid aliasing is deducted based on the Nyquist theorem. The mathematical relation supports the proposed ArcSAR system in acquiring data by setting the sampling angle interval. Third, the range cell migration (RCM) phenomenon is severe because mmwave radar has a wide azimuth beamwidth and a high frequency, and ArcSAR has a curved synthetic aperture. Therefore, the fourth-order RCM model based on the range-Doppler (RD) algorithm is interpreted with a uniform azimuth angle to suit the system and implemented. The proposed system uses the TI 6843 module as the radar sensor, and its azimuth beamwidth is 64°. The performance of the system and the corresponding imaging algorithm are thoroughly analyzed and validated via simulations and real data experiments. The output image covers a 360° and 180 m area at an azimuth resolution of 0.2°. The results show that the proposed system has good application prospects, and the design principles can support the improvement of current ArcSARs. Full article

Background and Objectives: This study aimed to evaluate the effects of hard, soft, and semi-soft splints on TMJ vibrations in bruxers with JVA and to compare them with data obtained from asymptomatic individuals. Materials and Methods: A total of 64 individuals were divided into four subgroups: control (n = 15); and hard (n = 17), soft (n = 16), and semi-soft (n = 16) splints. Electrovibratography records from all individuals included in the study before and after the 3-month splint treatment were obtained with the Biopak^® System. Joint vibration analysis was used to evaluate TMJ sounds. Data normality was examined with the Kolmogorov–Smirnov and Levene tests. The significance of the differences was investigated by One-Way ANOVA and by the Kruskal–Wallis test. Conover’s multiple comparison test was used in post hoc tests. (ClinicalTrials.gov identifier: NCT06893744, on 24 March 2025, titled; Effects of Different Occlusal Splints). Results: After 3 months of treatment, for I < 300 Hz right opening, the control group was statistically lower than both semi-soft (p < 0.001) and hard (p < 0.001) splint groups. The difference between semi-soft and hard splints in post-treatment I < 300 Hz right opening is not statistically significant. After 3 months of treatment compared with the beginning, the increases in left-opening Ti (p = 0.004), I < 300 Hz (p = 0.004), and PA (p = 0.007) values in the soft splint group were statistically significant. Conclusions: All three kinds of splints improved clinical symptoms and complaints of bruxers. For joint vibrations in bruxers, hard and semi-soft splints are more beneficial than soft splints. Full article

Background/Objectives: This study compares the accuracy of responses from state-of-the-art large language models (LLMs) to patient questions before CT and MRI imaging. We aim to demonstrate the potential of LLMs in improving workflow efficiency, while also highlighting risks such as misinformation. Methods: There were 57 CT-related and 64 MRI-related patient questions displayed to ChatGPT-4o, Claude 3.5 Sonnet, Google Gemini, and Mistral Large 2. Each answer was evaluated by two board-certified radiologists and scored for accuracy/correctness/likelihood to mislead using a 5-point Likert scale. Statistics compared LLM performance across question categories. Results: ChatGPT-4o achieved the highest average scores for CT-related questions and tied with Claude 3.5 Sonnet for MRI-related questions, with higher scores across all models for MRI (ChatGPT-4o: CT [4.52 (± 0.46)], MRI: [4.79 (± 0.37)]; Google Gemini: CT [4.44 (± 0.58)]; MRI [4.68 (± 0.58)]; Claude 3.5 Sonnet: CT [4.40 (± 0.59)]; MRI [4.79 (± 0.37)]; Mistral Large 2: CT [4.25 (± 0.54)]; MRI [4.74 (± 0.47)]). At least one response per LLM was rated as inaccurate, with Google Gemini answering most often potentially misleading (in 5.26% for CT and 2.34% for MRI). Mistral Large 2 was outperformed by ChatGPT-4o for all CT-related questions (p < 0.001) and by ChatGPT-4o (p = 0.003), Google Gemini (p = 0.022), and Claude 3.5 Sonnet (p = 0.004) for all CT Contrast media information questions. Conclusions: Even though all LLMs performed well overall and showed great potential for patient education, each model occasionally displayed potentially misleading information, highlighting the clinical application risk. Full article

Background and Objectives: Ovarian carcinosarcoma (OCS) is a rare gynecologic malignancy defined by both epithelial and mesenchymal components, generally associated with advanced clinical stage and poor outcomes. We present a 66-year-old patient initially presenting with right iliac vein thrombosis, ultimately diagnosed with OCS, and place these findings in context with a focused literature review from 2000 through to 2024. Methods: A comprehensive account of the patient’s clinical course—spanning diagnostic imaging, surgical pathology, neoadjuvant chemotherapy, and interval debulking—was combined with a review of the current data on OCS pathogenesis, treatment protocols, and outcomes. Results: The patient’s tumor showed predominantly sarcomatous histology (approximately 90%) with high-grade serous features, responded to platinum/taxane chemotherapy, and was resected to no visible residual disease. The updated literature indicates that the majority of OCS cases present at advanced stages (often exceeding 60%), with suboptimal cytoreduction closely tied to worse prognosis. Up to 64% of tumors may harbor homologous recombination deficiency, offering a rationale for PARP inhibitor therapy; nonetheless, five-year survival rarely surpasses 45% in most series. Conclusions: Despite its aggressive course, optimal debulking surgery plus platinum-based chemotherapy remain central in treating OCS. Emerging molecular insights highlight homologous recombination deficiency and BRCA mutations as potential therapeutic targets. Multidisciplinary care and future prospective studies are key to improving long-term outcomes in this challenging malignancy. Full article

Water molecules from the environment or human breath are one of the main factors affecting the accuracy, efficiency, and long-term stability of electronic gas sensors. In this contribution, yttrium (Y)-doped La₂Ti₂O₇ (LTO) nanosheets were synthesized by a hydrothermal reaction, demonstrating improved proton conductivity compared to their non-doped counterparts. The response of Y-doped LTO with the optimal doping concentration to 100 ppm NO₂ at 43% relative humidity (RH) was −21%, which is four times higher than that of bare La₂Ti₂O₇. As the humidity level increased to 75%, the response of Y-doped LTO further increased to −64%. Unlike the gas doping effect observed in previous studies of semiconducting metal oxides, the sensing mechanism of Y-doped LTO nanosheets is based on the enhanced dissociation of H₂O in the presence of target NO₂ molecules, leading to the generation of more protons for ion conduction. This also resulted in a greater resistance drop and thus a larger sensing response at elevated humidity levels. Our work demonstrates that proton-conductive oxide materials are promising gas-sensing materials under humid conditions. Full article